The invention relates generally to couplers for selectively interconnecting cranes and backhoes to various earth and material handling devices such as buckets, blades and claws and more specifically to a coupler which may be permanently attached to the crane boom or backhoe dipper stick which automatically attaches to and manually releases from a bucket, blade, claw or material handling attachment.
The broad utility of cranes and backhoes is apparent from the even broader array of attachments with which such devices are utilized. For example, buckets, grapples, blades, picks and hooks are all commonly used with cranes and backhoes. Furthermore, within the broad category of buckets are numerous styles and sizes intended for digging variously shaped trenches in diverse material or relocating materials, for example, from or to the ground or a dump truck.
With this versatility comes the attendant problem of interchanging such attachments on a given crane or backhoe. Given the specialization of attachments one particular attachment may only be utilized for a brief task and changing attachments becomes an ever present and time consuming problem.
The problem has not gone unaddressed. There exists a relatively extensive collection of devices having the purpose of permitting expeditious connection, use and release of one attachment and re-connection of another. Generally speaking, these devices can be segregated into two classes: those which require manual activation to connect and/or release an attachment and those which incorporate remotely controlled mechanisms which render the coupling and disconnection substantially automatic. Manually activated devices will be reviewed first.
U.S. Pat. No. 4,187,050 to Barbee teaches a quick disconnect coupling mechanism which includes a forward, curved member which opens to the rear and engages a forward crossbar on a bucket and a rear hook-like member which receives a rear bucket crossbar. The rear member pivots to a crossbar retaining position and is maintained there by a spring biased latch. U.S. Pat. No. 4,214,840 to Beales teaches a quick-release coupler having a pair of parallel crossbars which are received within correspondingly positioned, diversely oriented throats on a bucket which also includes a spring biased latch mechanism. A hydraulically operated latch mechanism is also disclosed.
In U.S. Pat. No. 4,297,074 to Ballinger, the bucket likewise includes a pair of parallel spaced-apart crossbars which are engaged by a coupling member having front throats and rear throats which are oriented at 90.degree. to one another. A pivotable locking clevis disposed on the rear bucket crossbar secures the coupler to the bucket. In U.S. Pat. No. 4,436,477 to Lenertz et al.. a coupler includes similarly oriented front and rear throats as well as a pivoting hook which translates to engage and retain a rear bucket crossbar in the rear throat of the coupler.
U.S. Pat. No. 4,632,595 to Schaeff utilizes a bucket having a forward crossbar member and rear plate. The coupler includes forward opening throats which engage the front crossbar member and a spring biased latch at the rear which hooks on the underside of the plate. Attachment is automatic and release requires manual translation of the hook to overcome a biasing spring.
U.S. Pat. No. 4,810,162 to Foster teaches another variation on a coupler having an open forward throat which engages a forward crossbar in a bucket and a moving member at the rear which pivots and engages a rear crossbar. The frame of the coupler includes slots for receiving the rear crossbar and a pivoting member spaced between the walls of the coupler which engages the bucket crossbar and pivots to retain the crossbar in the rear coupler slots. In U.S. Pat. No. 4,854,813 to Degeeter et al., the bucket includes forward and rearward circular reentrant regions which receive complementarily configured and disposed transverse members on the boom. A sliding latch is manually positioned to retain the bucket boom components in the re-entrant regions of the bucket.
U.S. Pat. No. 4,955,779 presents another connector wherein the bucket includes opposed re-entrant channels and the coupler includes complementarily disposed members which engage the reentrant portions and secure the bucket to the boom. In U.S. Pat. No. 4,986,722 to Kaczmarczyk et al., a combination of the above features are found. At the front of the bucket, a circular cross member is utilized which is engaged by a transverse slot on the boom coupler. At the rear of the bucket are a pair of spaced apart slotted members which receive a transverse circular member disposed on the boom. A manually operable latch retains the rear transverse boom member in the slots of the bucket.
The second group of prior art patents includes remotely activatable coupling devices. U.S. Pat. No. 4,355,945 to Pilch teaches a coupling mechanism similar to that disclosed in U.S. Pat. No. 4,436,477. The bucket includes a pair of transversely disposed spaced-apart crossbars and the coupler includes sidewalls slotted at the front to engage the front crossbar and a hydraulically operated pivotable hook which engages the rear crossbar and clamps the coupler thereto.
In U.S. Pat. No. 4,480,955, the bucket includes unique coupling features, namely, a forward triangularly configured crossbar and a rearward hook. The coupler includes complementary members, namely, a transversely disposed triangular notch at the front and a hydraulically operated wedge which engages the hook. U.S. Pat. No. 4,881,867 presents a coupler configured to engage parallel transversely oriented bucket crossbars. The coupler includes a first throat for engaging the forward crossbar and a hydraulically operated movable jaw extending from the coupler housing which engages the rear bucket crossbar. U.S. Pat. No. 4,944,628 teaches a novel locking mechanism wherein a hydraulic cylinder rotates a cam to couple and uncouple a bucket and boom.
The foregoing review of prior art patents reveals that improvements in the art of such coupling mechanisms are both possible and desirable. For example, many utilize non-standard interconnecting components which may only be used with complementarily configured devices, thereby limiting their versatility and adaptability. Others require the crane or backhoe operator to dismount to connect and disconnect the attachment. This can be a time consuming and frustrating task since the operator may have to adjust the crane or boom, dismount to connect the attachment or, if the boom is not properly positioned relative to the attachment, repeatedly remount and readjust the boom before it can be connected to the attachment.